Use of plastic cards as badges for entering and leaving access controlled areas or as "substitute money" in the form of check cards, bank cards, credit cards etc. is widespread and still increasing because of the automation of financial transaction methods. For storing data these cards in general contain magnetic strips. A significant problem associated with the use of cards of this nature is their unlawful use and the high monetary losses arising as a consequence of this unlawful use. In order to prevent such unlawful use, it is necessary to confirm that the person actually in possession of the card is the person authorized to have it.
It is known to use fingerprint verification systems for identity checks as described in U.S. Pat. No. 4,428,670 or in German Patent No. 27 40 483. In the identification process, the fingerprints are examined for certain characteristics of details of skin structures (island crossings of the dermal grooves, vortices, etc.) and the characteristic sequence of the features compared with a stored quantity and sequence and the identity of an individual determined as a function of them. To this end, terminals with fingerprint sensors are used, which are connected to a central numerical processor because of the large quantity of data involved.
Use of terminals connected to central numerical processors makes widespread use of such an identification system less feasible. In addition, a system using a central numerical processor is susceptible to interferences, expensive and difficult to handle.
A further problem is data security. Thus, when using plastic cards, precautions must be taken to make the stored data inaccessible to unauthorized personnel.
The fact that fingerprint identification systems in use until now attempted to determine the identity of the individual i.e. to derive from the fingerprints themselves the identity of the individual, these identification systems, therefore, ran counter to the desire for data protection in the application of the fingerprint identification systems for check cards, credit cards, etc.
It is therefore one object of the invention to make available an arrangement and a procedure of a high rate of accuracy for determining whether individuals are authorized users of information carrying cards by checking fingerprints independently of a central data processing facility. Another object is that, for reasons of data protection, the arrangement and the process should be such that unambiguous identity determination solely on the basis of fingerprints is not possible.